<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>后盾人</title>
    <style>
        a:link {
            color: red;
        }

        a:visited {
            color: yellow;
        }

        a:hover {
            color: green;
        }

        a:active {
            color: black;
        }

        input:focus {
            background: blue;
            outline: none
        }

        input:hover {
            background: red;
        }

        input:active {
            background: green;
        }
    </style>
</head>

<body>
    <main>
        <input type="text">
        <a href="https://www.houdunren.com">houdunren.com</a>
        <article>
            <h1 title="houdunren">后盾人</h1>
            <aside>
                <h2>houdunren.com</h2>
            </aside>
            <h2>hdcms.com</h2>
        </article>
    </main>
</body>

</html>